	public class ScientificCalculator implements BasicCalculator
	{
		int add(int num1, int num2)
		{
			return num1+num2;
		}
		
	public int sub(int num1,int num2)
	{
		return num1 - num2;
	}
	}

	interface BasicCalculator
	{
		int sub(int num1,int num2);
	}
	

	class Test
	{
		public static void main (String[] felight)
		{
			BasicCalculator basicCalc= new ScientificCalculator();
		}
}
